A conventional thermo shrinkable film machine generally includes a transmission wheel with a hole defined centrically therethrough and a shaft rotatably extends through the hole in the transmission wheel with a small gap defined between the inner periphery of the hole and the shaft. Two upper pressing wheels are located around the shaft so as to provide proper pressure on the thermo shrinkable film and to move film downward along the shaft. A cutting device is located beneath the transmission wheel so as to cut the film at pre-decided length. A positioning device is located beneath the transmission wheel and includes two lower pressing wheels which guide the film to be mounted to containers or cans. Two flexible plates are used to stop lower edge of the film which is not yet sent to mount on the containers or cans. A common problem is that the thickness of the film may vary due to the different manufacturers and the upper pressing and lower pressing wheels have to be adjusted accordingly by manual efforts and this spends a lot of time.
The present invention intends to provide an adjusting device which controls two wheels to contact the shrinkable film of different thickness synchronously.